Storefront and curtain wall framing systems are well known wherein a grid of frame members is erected and infill panels set into the openings in the grid. In a typical storefront or curtain wall framing system, the vertical frame members or mullions are typically continuous from the sill to the head, while the intermediate horizontal frame members or muntins extend only between adjacent vertical frame members and abut the adjacent vertical frame members at each end. The vertical frame members thus extend through the joints with the intermediate horizontals and are thus sometimes referred to as "through" frame members. The vertical frame member is usually the through frame member because of the load-bearing requirements placed on the verticals. However, some storefront and curtain wall framing systems employ horizontal through members in conjunction with vertical intermediate frame members.
Elastomeric weathering strips are typically applied along the vertical and horizontal frame members and bear against the marginal portions of the infill panel. While the through frame members extend through the joint with abutting intermediate frame members, the weathering strips which are applied to the through frame members do not extend through the joint. Instead, the weathering strips applied to the through mullions are cut to length to fit between adjacent intermediate mullions.
Storefront and curtain wall framing systems are typically internally drained. That is, moisture which collects on an upper surface of a horizontal frame member flows along that horizontal surface until it reaches the adjoining vertical frame member, where the water is drained into a cavity defined by the vertical frame member. The water then runs down along the vertical frame member to the bottom of the framing system, where it is discharged from the building.
As the water flows from the horizontal frame member to the vertical frame member, it flows past the metal-to-metal joint between the through frame member and the abutting intermediate frame member. If there is a pressure differential between the interior and the exterior of the building, such as would be the case when the building is under wind load, water can be drawn between the through frame member and the end of the abutting frame member to the interior of the building. To prevent water and air infiltration through this metal-to-metal joint, it is necessary to seal the joint.
Such joints are typically sealed by applying a sealant to the joint after the frame members have been assembled. However, there are numerous disadvantages associated with this type of sealing arrangement. First, "wetsealing" the joint is labor intensive, both in terms of application of the sealant and subsequent clean up. And if the sealant is applied by unskilled or careless labor, it is possible for the joint to leak. Also, it is not practical to apply the sealant prior to erection of the framing system. While it is common for the vertical and horizontal frame members to be assembled into a grid prior to being shipped to the job site, racking or twisting of the grid during shipment for installation could disrupt any joint seal created by applying a sealant to the joint prior to shipping the framing system to the job site.
Thus there is a need for a system for sealing a joint between a through frame member and an abutting intermediate frame member which is not labor intensive to apply. There is a further need for sealing a joint between a through frame member and an abutting intermediate frame member which avoids the problem of defective joint seals caused by misapplication of a sealant at the job site by unskilled or careless labor.
There is still a further need for sealing a joint between a through frame member and an abutting intermediate frame member in which the seal can be applied prior to shipping the framing system to the job site.